Optimal decision-making requires that stimulus-value associations are kept up to date by constantly comparing the expected value of a stimulus with its experienced outcome. To do this, value information must be held in mind when a stimulus and outcome are separated in time. However, little is known about the neural mechanisms of working memory (WM) for value. Contradicting theories have suggested WM requires either persistent or transient neuronal activity, with stable or dynamic representations, respectively. To test these hypotheses, we recorded neuronal activity in the orbitofrontal and anterior cingulate cortex of two monkeys performing a valuation task. We found that features of all hypotheses were simultaneously present in prefrontal activity, and no single hypothesis was exclusively supported. Instead, mixed dynamics supported robust, time invariant value representations while also encoding the information in a temporally specific manner. We suggest that this hybrid coding is a critical mechanism supporting flexible cognitive abilities.

中文翻译：

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前额叶皮层中价值的稳定和动态表示

最佳决策要求通过不断将刺激的预期值与其经历的结果进行比较来保持刺激与价值的关联。为此，当刺激和结果在时间上分开时，必须牢记价值信息。然而，人们对价值的工作记忆 (WM) 的神经机制知之甚少。相互矛盾的理论表明，WM 需要持续或短暂的神经元活动，分别具有稳定或动态的表征。为了验证这些假设，我们记录了执行评估任务的两只猴子的眶额和前扣带皮层的神经元活动。我们发现所有假设的特征同时存在于前额叶活动中，并且没有单一假设得到完全支持。相反，混合动力支持稳健，时不变的值表示，同时还以时间特定的方式对信息进行编码。我们认为这种混合编码是支持灵活认知能力的关键机制。